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Insydeh2oApplication · Insyde

CVE-2021-45969

HIGH · 8.2 CVSS v3.1 Published 2022-01-05
Fix available
A fix is available. Upgrade to 5.16.25 / 5.26.25 or later.
See remediation →
84/100
Remediation priority · High
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An issue was discovered in AhciBusDxe in Insyde InsydeH2O with kernel 5.1 before 05.16.25, 5.2 before 05.26.25, 5.3 before 05.35.25, 5.4 before 05.43.25, and 5.5 before 05.51.25. A vulnerability exists in the SMM (System Management Mode) branch that registers a SWSMI handler that does not sufficiently check or validate the allocated buffer pointer (the CommBuffer+8 location).

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Vulnerability in AhciBusDxe UEFI driver in InsydeH2O kernel versions 5.1-5.5. The SMM (System Management Mode) SWSMI handler fails to properly validate a buffer pointer at CommBuffer+8 location, potentially allowing arbitrary code execution in SMM privilege level.

MitigationApply vendor-supplied UEFI firmware update for affected kernel versions (5.1 to 05.16.25, 5.2 to 05.26.25, 5.3 to 05.35.25, 5.4 to 05.43.25, 5.5 to 05.51.25). If patching is not feasible, restrict physical access and ensure secure boot protections are enabled.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Insydeh2oApplication
Affected:>= 5.1, < 5.16.25>= 5.2, < 5.26.25>= 5.3, < 5.35.25>= 5.4, < 5.43.25>= 5.5, < 05.51.25

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
High
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify if system uses InsydeH2O firmware
    Run 'dmidecode -s bios-vendor' or check UEFI/BIOS setup screen for the firmware vendor name. InsydeH2O systems will show Insyde as the BIOS vendor.
    Affected if The system does not use InsydeH2O firmware (different vendor such as AMI, Phoenix, or OEM-custom).
  2. Get the InsydeH2O kernel version
    Run 'dmidecode -s bios-version' or check the UEFI/BIOS setup screen for the firmware version string. Extract the kernel version number (e.g., 5.1, 5.4, 5.5, etc.).
    Affected if Unable to retrieve the firmware version or the version string does not contain an InsydeH2O kernel version number.
  3. Compare installed version against affected ranges
    Match the extracted version against: 5.1 to <5.16.25, 5.2 to <5.26.25, 5.3 to <5.35.25, 5.4 to <5.43.25, or 5.5 to <05.51.25. Note that versions before 5.1 are not listed as affected.
    Affected if The installed version falls within any of the affected ranges listed (5.1 through 5.5 series with the specified upper limits).
  4. Verify AHCI/SATA controller is present and enabled
    Check system for AHCI SATA controller: run 'lspci | grep -i sata' or check UEFI/BIOS setup under SATA/Storage configuration for AHCI mode.
    Affected if No AHCI SATA controller is present or AHCI is not enabled in firmware settings.
  5. Confirm SMM is accessible
    The vulnerability exploits SMM. Check if SMM is enabled: run 'dmidecode' or check UEFI settings for SMM configuration. Some systems show SMM in 'dmidecode -t bios' output.
    Affected if SMM is disabled or unavailable (uncommon on typical systems).

A system is affected if it uses InsydeH2O firmware with a kernel version falling within the listed affected ranges AND has an AHCI SATA controller enabled with SMM available.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.16.25 / 5.26.25 / 5.35.25 or later
Fixed in 5.16.255.26.255.35.25
Interim mitigation

Apply vendor-supplied UEFI firmware update for affected kernel versions (5.1 to 05.16.25, 5.2 to 05.26.25, 5.3 to 05.35.25, 5.4 to 05.43.25, 5.5 to 05.51.25). If patching is not feasible, restrict physical access and ensure secure boot protections are enabled.

Recommended fix High confidence

Upgrade to InsydeH2O kernel 5.1 >= 05.16.25, 5.2 >= 05.26.25, 5.3 >= 05.35.25, 5.4 >= 05.43.25, or 5.5 >= 05.51.25

  1. 1. Identify the current InsydeH2O firmware version installed on the affected system
  2. 2. Check the Insyde security advisory (www.insyde.com) for the specific firmware version corresponding to your kernel branch (5.1, 5.2, 5.3, 5.4, or 5.5)
  3. 3. Obtain the updated firmware version from your system vendor (OEM) that includes the fix: 05.16.25 (kernel 5.1), 05.26.25 (kernel 5.2), 05.35.25 (kernel 5.3), 05.43.25 (kernel 5.4), or 05.51.25 (kernel 5.5)
  4. 4. Apply the firmware update following the vendor's standard BIOS/UEFI update procedure
  5. 5. Verify the firmware version has been successfully updated after reboot
Caveat UEFI firmware updates carry a risk of system brick if interrupted; ensure stable power and follow vendor update procedures precisely

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Insydeh2o Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,600
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-45969 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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